"Mathlete" Alexis Lemaire, 27, found the answer to the 13th root of a random 200-digit number in 70.2 seconds by sheer brain power - beating his own world record of 72.4 seconds he set in November.

Alexis Lemaire correctly calculated an answer of 2,407,899,893,032,210 from the possibility of 393 trillion answers at London's Science Museum today. He used a computer package which randomly generated a 200-digit number. As soon as the number appeared, he began to calculate its 13th root. When he had the answer, he typed it into the computer, which told him he had the right answer and how fast he made his calculation.

Jane Wess, curator of mathematics at the London Science Museum said: “He sat down and it was all very quiet - and all of a sudden he amazingly just cracked it. “He seems to have a large memory and he’s made this his life’s ambition. It’s quite remarkable to see it happen. "A very small number of people have this extraordinary ability; nowadays there is only a handful. “I believe that it is the highest sum calculated mentally.”

The University of Reims student began honing his calculation skills by finding the 13th root of a random 100 digit number. But that became too easy for the mathematical mastermind in 2004 when he calculated an answer in less than four seconds so he stopped trying to improve his time.

Nowadays he tries to find the 13th root of a random 200-digit number to train his brain. Lemaire broke the record in the Science Museum’s History of Computing galley. It is the home of Charles Babbage’s Difference Engine No.2, the world’s first successful mechanical calculator, designed in the 1840s.

Lemaire had said before he smashed the world record: “I am pleased to be able to make my latest world-record attempt at the Science Museum. “I have been training very hard and I am confident I can break the world record.”Source